Hi Yuvvraj,
DO you have any break through ?
In my case, while uninstalling SAP on DB2 9.7 FP4 has gave error
FCO-00011 The step ChooseToDropDatabaseOrSchema with step key |NW_Uninstall|ind|ind|ind|ind|0|0|NW_System_Uninstall|ind|ind|ind|ind|uninstall|0|NW_uninstallDB|ind|ind|ind|ind|uninstDB|0|NW_DB6_Uninstall|ind|ind|ind|ind|db6_uninstall|0|ChooseToDropDatabaseOrSchema was executed with status ERROR ( Last error reported by the step: Error occured, first error is: <SQL5035N The database must be upgraded to the current release. >).
Kindly help.